This invention relates to a color image reproduction system and, more particularly, to a system wherein images recorded by an imaging member are read out with illumination from an extended light source.
There is known in the art a class of imaging members wherein a photoconductive layer and an elastically deformable layer are sandwiched between a pair of electrodes, one of which may be a thin flexible metallic layer overlying the elastomer layer. In operation imagewise activating electromagnetic radiation is directed upon the member and an electrical field is established across the photoconductive and elastomer layers thus causing these layers to deform in imagewise configuration. These members may be used as image intensifiers since the deformation image may then be read out with a high intensity light source and a schlieren optical system or for buffer storage of images since the images may be stored for some period of time. A family of imaging devices of this type is described in U.S. Pat. No. 3,716,359.
There has now been developed a color imaging system wherein there is utilized an imaging member of the type described in the '359 patent which further includes color spatial light modulation means and a fiber optic element. This color imaging system is described in copending Application, Ser. No. 507,910, filed on even date herewith in the name of Richard F. Bergen and assigned to a common assignee. The entire contents of this copending Application are hereby incorporated by reference herein. There is disclosed a readout scheme for full color readout wherein a point or small source readout light source is used. These small sources generally include an arc lamp or small filament bulbs. The former requires a relatively expensive power supply and large lamphouse and the latter typically has low output intensity.
Since an extended light source such as a slide projector lamp produces considerable intensity using standard voltage it would be an attractive candidate for a readout light source. However, the large area filament of such a light source would require a much higher carrier frequency for the imaging member to provide separation of the zero order from the diffracted orders in the Fourier plane of the readout lens. This in turn would typically require larger and more expensive readout optics and much more expensive color gratings. It would be desirable to have a readout optics system which includes an extended light source which does not have the above-noted disadvantages.